Six-Year Study Indicates Nipah Virus More Widespread than Previously Thought

NEW YORK – November 2, 2020 – In annual outbreaks throughout Bangladesh, Nipah virus kills around 70 percent of the people it infects. The virus, a distant relative of measles, has no vaccine and no proven medical countermeasures. EcoHealth Alliance, a nonprofit working at the intersection of animal, environmental, and human health on a global scale, released Monday the results of a major six-year study to understand how these outbreaks begin and how to prevent them.

Outbreaks typically occur within what is known as the “Nipah belt,” which stretches along Bangladesh’s western border with India. But EcoHealth Alliance scientists found that bats throughout Bangladesh had relatively similar patterns of Nipah virus infection. The research is published in the journal Proceedings of the National Academy of Sciences of the United States of America.

"Nipah circulates regularly in large fruit eating bats throughout many parts of Asia, but human outbreaks can only occur where there is a route of transmission from bats to humans," EcoHealth Alliance Vice President for Science and Outreach Dr. Jonathan Epstein said."The problem is, we don’t have a good handle on where else in the world spillover may be happening, which means we’re likely missing outbreaks. Risk is not so much limited by geography as it is by human behavior. This is a virus that spreads from person to person and is lethal in three quarters of those it infects, which is why we have to pay close attention to it and do what we can to prevent outbreaks."

Nipah outbreaks have been linked to consumption of raw date palm sap, as well as infection through an intermediate host such as domesticated animals such as pigs.

Of eight bat colonies studied across Bangladesh over a period from 2006 to 2012, researchers from EcoHealth Alliance and its partners found Nipah antibodies present in each location. In one bat colony studied continuously for six years, outbreaks in the bats occurred about every two years, about time it takes for bats to lose herd immunity. Outbreaks in bats can lead to human outbreaks, when there is a route of transmission available. Nipah virus, which in humans leads to brain swelling and often leaves patients in a coma, is already identified as one of the World Health Organization’s highest priority pathogens for vaccine development.

"Finding that bats carrying Nipah virus can be infected anywhere and at any time of year means we have to pay closer attention in areas where Nipah outbreaks may not have been previously reported, to make sure we’re not missing small outbreaks that could lead to bigger ones, " Dr. Epstein, the paper’s lead author, said.

The study also found that the strains of Nipah virus that cause human outbreaks reflect the strains carried by local bats, and that there were different strains of Nipah virus in different areas of the country. Genetic differences in the virus may impact disease severity or transmissibility in humans, something Dr. Epstein is currently studying under new funding from the National Institutes of Health.

Outside of India and Bangladesh, previous outbreaks of Nipah have occurred in Malaysia, Singapore, and the Philippines.

About EcoHealth Alliance:
Building on 45 years of groundbreaking science, EcoHealth Alliance is the premier nonprofit organization committed to a One Health approach to track the migration of deadly viruses from animals into humans. EcoHealth Alliance research has led to major breakthroughs on the origins and spread of new and emerging diseases like Ebola, SARS, MERS, Nipah virus, and, now, SARS-CoV-2. EcoHealth Alliance works globally in hotspot regions where the threat of outbreaks is highest. Through innovations in research, training, capacity building, and policy initiatives, we develop tools and interventions to prevent pandemics and promote conservation.
Press contact: Robert Kessler, (212) 380-4469 or kessler@ecohealthalliance.org.

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